A problem on which the invention is based is explained below with reference to the production of a rudder unit for an aircraft. However, this is not to be considered as a limitation for the method according to the invention which can be used in general for joining stringers to structural components.
The surface of a rudder unit of an aircraft is formed essentially by panel elements. Supporting stringers which impart the necessary rigidity to the rudder unit and which connect the individual panel elements to one another are arranged within the rudder unit. The stringers are typically formed by “I-shaped stringers”.
For the production of a rudder unit which may be produced entirely from fiber composite materials, in particular the outer panel elements and the inner I-shaped stringers, suitable methods are required to ensure that the I-shaped stringers are joined to the panel elements.
A method known to the applicant makes provision to supply the panel elements in the form of un-impregnated semifinished fiber products. The I-shaped stringers are arranged on the panel elements. The semifinished fiber product of the panel elements is then impregnated by means of an injection method. The stringers resting on the surface of the panel elements are wetted in the process by the resin and stuck on.
However, the following has proved disadvantageous in this case. The injection method requires a vacuum film to be arranged with a positive fit on the surface of the panel element and the I-shaped stringers. Laying the vacuum film with a positive fit along the step which is formed by the I-shaped stringer resting on said surface and the panel elements is complicated. This is because, inter alia, the step has a low height corresponding to the wall thickness of the I-shaped stringers. For conventional mechanical film laying apparatuses, this height is not sufficient in order to press the film onto the vertical profile of the step. Consequently, the covered vacuum films require at east one complicated manual finishing operation.